1. Field of the Invention
This invention relates to a method of manufacturing a socket of a tube coupler for connecting thereto a plug or a corrugated tube as a connected member by making a relative rotation between the tube coupler and the connected member.
2. Description of the Related Art
The socket of a conventional tube coupler which has a relatively simple structure and easily operable locking means comprises a tubular body projecting from a socket adapter and having lock grooves each consisting of an elongated hole in an inclined relation with the axis of the tubular body and a secondary hole extending axially of the tubular body from one end of the elongated hole, and pins fixed to the socket main cylinder through the lock grooves.
The socket of another conventional tube coupler comprises a tubular body constituting a socket main cylinder projecting from a socket adapter, and lock grooves each consisting of a first hole extending along the axis of the tubular body and opened at the forward end of the tubular body, a second hole continuous to the first hole and extending slantwise of the axis of the tubular body and a third hole continuous to the second hole and extending in the circumferential direction of the tubular body. The pins fixed to the outer periphery of a plug are made to engage the corresponding lock grooves, thereby to insert the plug in the socket main cylinder.
U.S. Pat. Nos. 4,875,720; 4,904,002; 4,907,830; and 4,904,001 disclose further similar tube couplers.
The tubular bodies used in the above-mentioned tube couplers are manufactured from hollow cylindrical tubes. Therefore, the lock grooves must be formed only by cutting. The cutting process, however, has a drawback that it is very time-consuming.